Fabrication for electroplating thick metal pads
View Patent ↗A method of electroplating includes forming a seed region to be electroplated on a first portion of a substrate, forming a ground plane on a second portion of a substrate, electrically isolating the ground plane from the seed region, electroplating the region, wherein electroplating includes causing the ground plane and the region to make electrical connection, and then removing the ground plane region on the second portion of the substrate, but not removing the electrical isolation. This creates a structure having a substrate, a passivation layer on the substrate, and at least one electroplated, metal region on the substrate such that there is contiguous contact between the metal region and the passivation layer. And, after an additional flip-chip assembly to a bond pad/heat sinking chip, results in a device having a bond pad chip having bond pads, solder beads formed on the bond pads, and a component connected to the bond pads by the solder beads. Wherein, the component has a substrate, a passivation layer on the substrate, and at least one electroplated, metal region on the substrate such that there is contiguous contact between the metal region and the passivation layer.
1. A method of electroplating, comprising:
forming a seed region to be electroplated on a first portion of a substrate;
forming a ground plane on a second portion of a substrate such that the ground plane is electrically isolated from the seed region;
electroplating the seed region, wherein electroplating includes causing the ground plane and the seed region to make electrical connection; and
removing the ground plane from the second portion of the substrate by reacting the ground plane into an electrical passivation layer upon completion of the electroplating.
2. The method of claim 1 , wherein forming a ground plane comprises depositing a passivation layer between the seed region and the ground plane to electrically isolate the ground plane from the region.
3. The method of claim 2 , wherein depositing the passivation layer comprises depositing the passivation layer resistant to the ground plate material removal process.
4. The method of claim 2 , wherein depositing the passivation layer further comprises depositing one of silicon nitride or silicon dioxide.
5. The method of claim 1 , wherein forming the seed region to be electroplated comprises forming a layer of metal comprised of one of gold, titanium, molybdenum, nickel, niobium, or aluminum.
6. The method of claim 1 , wherein forming the region to be electroplated comprises forming an n-contact region and a p-contact region for a light emitting diode.
7. The method of claim 1 , wherein forming the ground plane comprises forming a ground plane over the first and second portions of the substrate and selectively removing the ground plane from the first portion.
8. The method of claim 1 , wherein removing the ground plane from the second portion does not affect the electrical isolation characteristics of the passivation layer.
9. The method of claim 1 , wherein forming the ground plane further comprises forming a layer of one of titanium, titanium-tungsten or tungsten.
10. The method of claim 1 , wherein electroplating the region includes forming at least one initial metal bead.
11. The method of claim 10 , wherein forming the initial metal bead causes the ground plane to short to a seed region to be electroplated, resulting in electroplating on that region.
12. The method of claim 1 , wherein the method employs a single photolithographic process.